Within the scope of this work, a new test procedure for O-rings was developed, which is intended to provide information on the deformation behaviour under compressive load. A test specimen holder for O-rings designed for this purpose, consisting of a static flange seal with a transparent flange cover, enabled the optical measurement of the changing O-ring dimensions by means of a camera system. This test specimen holder was implemented in an autoclave with a viewing window for the necessary pressure build-up. The second focus was about the creation of a finite element analysis (FEA) of a static O-ring flange gasket. For the simulation of the real material behaviour, data from material tests with different load modes (uniaxial, biaxial and pure shear) were implemented in the simulation program in order to select a suitable hyperelastic material model. Two elastomer materials (HNBR and TPU) were used for the analysis. A comparison of the FEA and the experimental tests, with the aim of validating the FEA, was then carried out. The results showed that an optical measurement of the behaviour of O-rings under pressure load is possible in real time for a static flange gasket. The optical recordings could be evaluated with a video analysis tool. For the FEA, a hyperelastic material model could be selected for both materials. In the case of HNBR, the fillers lead to higher deviations between the data of the material tests and the material model. During the validation of the FEA, deviations in the contact behaviour and behaviour of the investigated points could be determined with deviations of several tenths of a millimetre. Responsible for this are the factors of permeation, contact behaviour, temperature influence, swelling and relaxation, which form the basis of a very complex material behaviour. Finally, however, a correlation of the component characterization with the FEA could be demonstrated.